Temperature dependent calibration of movement detection devices

ABSTRACT

An electronics system has a board with a thermal interface having an exposed surface. A thermoelectric device is placed against the thermal interface to heat the board. Heat transfers through the board from a first region where the thermal interface is located to a second region where an electronics device is mounted. The electronics device has a temperature sensor that detects the temperature of the electronics device. The temperature of the electronics device is used to calibrate an accelerometer and a gyroscope in the electronics device. Calibration data includes a temperature and a corresponding acceleration offset and a corresponding angle offset. A field computer simultaneously senses a temperature, an acceleration and an angle from the temperature sensor, accelerometer and gyroscope and adjusts the measured data with the offset data at the same temperature. The field computer provides corrected data to a controlled system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase of International Application No.PCT/US2019/043099, filed on Jul. 23, 2019, which claims priority fromU.S. Provisional Patent Application No. 62/702,870, filed on Jul. 24,2018, all of which are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION 1). Field of the Invention

This invention relates generally to an electronics system, a method ofconstructing an electronics system and a method of operating anelectronics device, and more specifically to calibration of movementdetection devices.

2). Discussion of Related Art

Electronics devices such as semiconductor chips frequently includemovement detection devices such as accelerometers and gyroscopes. Anaccelerometer can detect acceleration of the electronics device in aspecified direction and a gyroscope can detect a change in angle of theelectronics device. Such measurement devices are usually manufacturedusing microelectromechanical systems (MEMS) technology.

SUMMARY OF THE INVENTION

The invention provides an electronics system including a board. Theboard may include a structural material, a thermal conduit on thestructural material, the thermal conduit having a thermal conductivitythat is higher than a thermal conductivity of the structural materialand having a first region, a second region, and a connecting portionconnecting the first region to the second region, a thermal interface onthe structural material, the thermal interface having a thermal heattransfer capacity that is higher than the thermal heat transfer capacityof the structural material and being attached to the first region of thethermal conduit and an electronics device mounted to the board at thesecond region of the thermal conduit, the thermal conduit forming athermal path between the surface of the thermal interface and theelectronics device.

The invention also provides a method of constructing an electronicssystem including constructing a board that may include forming a thermalconduit on the structural material, the thermal conduit having a thermalheat transfer capacity that is higher than a thermal heat transfercapacity of the structural material and having a first region, a secondregion, and a connecting portion connecting the first region to thesecond region, forming a thermal interface on the structural material,the thermal interface having a thermal heat transfer capacityconductivity that is higher than the thermal heat transfer capacity ofthe structural material and being attached to the first region of thethermal conduit and mounting an electronics device to the board at thesecond region of the thermal conduit, the thermal conduit forming athermal path between the surface of the thermal interface and theelectronics device.

The invention further provides a method of operating an electronicsdevice including operating an electronics device mounted to a board,locating a thermal device adjacent a thermal interface of the boardformed on a structural material of the board and transferring heatbetween the thermal device and the electronics device through a thermalconduit on the structural material, the thermal conduit having a thermalheat transfer capacity that is higher than a thermal heat transfercapacity of the structural material and having a first region attachedto the thermal interface, a second region at the electronics device, anda connecting portion connecting the first region to the second region.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described by way of examples with reference to theaccompanying drawings, wherein:

FIG. 1 is a top view in a first plane of an electronics system accordingto an embodiment of the invention;

FIG. 2 is a cross-sectional side view of the electronics system in asecond plane on 2-2 in FIG. 1 ;

FIG. 3 is a cross-sectional side view of the electronics system in athird plane on 3-3 in FIG. 1 ;

FIG. 4 is a side view similar to FIG. 1 and further illustrates anelectronics device forming part of the electronics system;

FIG. 5 is cross-sectional side view on 5-5 in FIG. 4 showing with to aclose-up detailed view of the electronics device;

FIG. 6 is a cross-sectional side view of the electronics system furtherillustrating a calibration station;

FIG. 7 is a cross-sectional side view of the electronics system furtherillustrating the use of the calibration station to heat and calibratethe electronics device of the electronics system;

FIG. 8 is cross-sectional side view of the electronics system, furthershowing a field computer and a controlled system that uses calibrationdata; and

FIG. 9 is a cross-sectional side view of an electronics system accordingto another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Output readings from movement detection devices, such as accelerometersand gyroscopes, can be affected by changes in temperature of thedevices, thereby introducing temperature-dependent error in the outputmeasurements. For example, an accelerometer at rest should provide anoutput measurement corresponding to gravitational acceleration; howeverwhen the accelerometer is subjected to different temperatures, theoutput measurement will be different due to error associated with theaccelerometer being at a higher temperature. Because the output shouldnot change while the accelerometer is at rest, that is, acceleration isstill only gravity regardless of the temperature, it is possible toisolate the output measurement error associated with temperature byfinding the difference (or “offset”) between the erroneous measurementand the known baseline measurement (gravity in the case of anaccelerometer). By conducting this measurement comparison at multipletemperatures, many data points are collected and an offset profile overa range of temperatures can be obtained. The collection of dataassociating temperatures with specific offset readings can be compiledfor each movement detection device during the calibration process. Thedata can be stored as calibration data in a table for look up orextrapolation, or can be used to define a best fit function. Thecalibration data can be accessed by a virtual reality, augmentedreality, or mixed reality system to obtain an adjusted measurement froma movement detection device given the temperature of the movementdetection device and its initial “raw” measurement.

A calibration system and process that improves calibration accuracy isdescribed herein. Known methods of calibrating movement detectiondevices involve contacting the movement detection device with a thermalprobe to introduce heat by conduction or require actively blowing airacross the movement detection device to adjust its temperature byconvection. Both of these methods can cause the device to move so that ameasurement taken from the device during calibration will include anerror associated with temperature and an error associated with movementintroduced by the measurement method. Because it is not possible to knowhow much movement is introduced by the measurement method, it is notpossible to isolate the error associated with temperature. As a result,the error cannot be accurately removed from the raw output measurementof the device. In virtual, augmented, and mixed reality systems, theaccuracy of a measurement taken by a device is critical for determiningwhere to display virtual content to a user with respect to movementbetween the user and the real or virtual environment. Thus, there existsa need for a highly accurate calibration system and method in a virtual,augmented, or mixed reality device.

FIGS. 1, 2 and 3 illustrate an electronics system 10, according to anembodiment of the disclosure. FIG. 1 is a top view of an exampleconfiguration of a board 12 in the electronics system 10. FIG. 2 is across-sectional side view on 2-2 in FIG. 1 . FIG. 3 is a cross-sectionalside view on 3-3 in FIG. 1 . The electronics system 10 includes a board12 made up of multiple layers of different materials. The layers andvarious features disposed therein provide particular functions duringcalibration and use of an electronics device 14 (discussed with respectto FIGS. 4 and 5 ), such as a sensor or sensor suite, connected to theboard 12.

The board 12 is constructed from structural material 22, such as FR4dielectric, and a thermally and electrically conductive material, suchas metal components 24. Metal components 24 may include a coppermaterial. The metal of the metal components 24 is more thermallyconductive, and therefore has a higher thermal heat transfer capacity,than the structural material 22. The metal of the metal components 24 iselectrically conductive and the structural material 22 is electricallyinsulating.

Multiple layers of structural material 22 can be included in the board12. As shown in the example of FIGS. 2 and 3 , two structural layers 28and 30 can be provided. The metal components 24 are disposed between thelayers of structural material 22. For example, the metal components 24can include first, second and third metal layers 34, 36 and 38 separatedby the first and second structural layers 28 and 30. The board 12further includes top and bottom insulating layers 32 and 26 that coverthe first and third metal layers 34 and 38. The top and bottominsulating layers 32 and 26 can include an electrically insulatingsolder resist material 25.

The metal components 24 also include first and second sets of vias 40and 42, respectively. The first set of vias 40 connects portions of thefirst metal layer 34 to portions of the second metal layer 36. Thesecond set of vias 42 connects portions of the second metal layer 36 toportions of the third metal layer 38. The metal layers 34, 36 and 38 arethereby electrically and thermally connected to one another. The metallayers 34, 36 and 38 together with the first and second sets of vias 40and 42 form a thermal conduit of thermally conductive material thatconnect a first region 46 of the thermal conduit to a second region 48of the thermal conduit.

Portions of the third metal layer 38 are isolated as metal lines 76 tofunction as traces for electrical signals. These metal lines 76 can beisolated from each other and from other metal components 24 such thateach line is surrounded by non-conductive material, such as dielectricstructural material 22 and insulating solder resist material 25. One ofskill in the art will appreciate that more or fewer than three metallines 76 may be provided depending on the design of the electronicdevice 14 that is mounted to the board 12 at the second region 48. Themetal lines 76 may be disposed in one or more of the metal layers in theboard 12. Additionally, while the lines 76 are shown as exposed parts ofthe metal component 24, portions of the metal lines 76 can also becoated with the insulating solder resist material 25.

The metal components 24 further include a thermal interface 52. Thethermal interface 52 is an area of the third metal layer 38 at the firstregion 46 that has been exposed by removing a portion of the topinsulating layer 32. The thermal interface 52 is an upper surface 54 ofthird metal layer 38 that is exposed and is configured to contact partof an electronic device calibration station 80. The upper surface 54forms only a portion of an upper surface of the board 12, with theremainder of the upper surface consisting of an upper surface of thestructural layer 30 and insulating solder resist layer 32.

Referring to FIGS. 1 and 2 in combination, the first, second, and thirdmetal layers 34, 36, 38 have an inner portion 58 and an outer portion60. The structural material 22 forms a plurality of barriers 62 thatdistinguish the inner portion 58 from the outer portion 60. The barriers62 act as thermal barriers to prevent heat from conducting from theinner portion 58 to the outer portion 60 of the second metal layer 36,or at least substantially slow the transfer of heat so that the outerportion 60 is kept cooler than the inner portion 58. Additionalelectronic components can be connected to the board 12. Such componentscan be connected to the board 12 at the outer portion 60 to keep thecomponents from experiencing high heat during the calibration process.

Referring to FIGS. 1 and 3 in combination, it can be seen that thefirst, second, and third metal layers 34, 36, 38 also have connectingportions 64 that connect the inner portion 58 to the outer portion 60.The connecting portions 64 ensure that the metal layers are electricallygrounded such that there is an equal reference voltage between the innerportion 58 and the outer portion 60.

Referring to FIGS. 1 and 2 in combination, it can be seen that similarthermal barriers 62 are formed at one or more positions within thefirst, second and third metal layers 34, 36 and 38 (FIG. 1 ) and thateach metal layer has respective portions 64 connecting inner and outerregions thereof. The barriers 62 prevent, or at least slow heat transferfrom the inner portion 58 to the outer portion 60 to protect othercomponents attached to the board 12 from experiencing high temperaturesduring the calibration of electronics device 14.

Referring to FIGS. 4 and 5 , the electronics system 10 further includesan electronics device 14 and a system storage 18. The electronics device14 is mounted to an upper surface of the board 12 through connections74. The electronics device 14 and the thermal interface 52 are withinthe barriers 62 that define the inner portion 58. The electronics device14 is mounted above the second region 48 of the thermal conduitdescribed above.

The electronics system 10 further includes a board interface 16 that isattached to the board 12 and connected to the measurement devices in theelectronics device 14. The electronics device 14 includes a structuralbody 66 and a number measurement devices in the structural body 66. Themeasurement devices include a temperature sensor 68 and two movementdetection device in the form of an accelerometer 70 and a gyroscope 72.Although two movement detection devices are used for purposes of thisembodiment, it may be possible to implement aspects of the inventionusing only one measurement device. It may for example be possible tocalibrate an electronics device having only a gyroscope or only anaccelerometer. The structural body 66 may, for example, be a silicon orother semiconductor structural body that may be packaged usingconventional packaging technologies. The temperature sensor 68,accelerometer 70 and gyroscope 72 are connected through connectors 74 onan upper surface of the board 12 and metal lines 76 in the board 12 tothe board interface 16. Data traces from the temperature sensor 68,accelerometer 70, and gyroscope 72 are routed to a microprocessor 73 inthe structural body 66 which serves as an input/output interface for themeasurement devices. The system storage 18 serves to store calibrationdata received from the calibration station 80 that is associated withthe accelerometer 70 and gyroscope 72. The system storage 18 may, forexample, include a solid-state memory. The system storage 18 is shownnear the electronics device 14, however, the system storage may be aremote storage, located on a cloud-based storage or on another area ofthe electronics device such that it is not in contact with the board 12.One of skill in the art will appreciate that the system storage 18 maybe located anywhere that is in communication with electronics device 14to allow for data transfer between electronics device 14 and systemstorage 18. The system storage 18 includes no calibration dataimmediately after the electronics system 10 has been assembled (that is,prior to undergoing calibration) but is uniquely associated with theelectronics device 14 by enabling data to transfer between theelectronics device 14 and the system storage 18.

FIG. 6 further illustrates a calibration station 80 that is used tocalibrate the accelerometer 70 and the gyroscope 72. The calibrationstation 80 includes a frame 82, a calibration computer 84, a calibrationcomputer interface 86, a thermoelectric device 88, a transformer 90 andan electric power connector 92. The components of the calibrationstation 80 are mounted in a stationary position to one another via theframe 82. A spacing between the calibration computer interface 86 andthe thermoelectric device 88 is the same as a spacing between the boardinterface 16 and the thermal interface 52. The calibration computer 84is connected to the calibration computer interface 86 so that signalscan transmit between the calibration computer 84 and the calibrationcomputer interface 86. Information from the microprocessor 73 can beaccessed by the calibration station 80. The calibration computer 84 isconnected to the electric power connector 92 so that power can beprovided through the electric power connector 92 to the calibrationcomputer 84. The thermoelectric device 88 is connected through thetransformer 90 to the electric power connector 92. The power can beprovided by the electric power connector 92 through the transformer 90to the thermoelectric device 88. The transformer 90 reduces the voltageprovided by the electric power connector 92 before providing power tothe thermoelectric device 88. The thermoelectric device 88 is preferablya reversible heat pump, such as a thermoelectric cooler, capable ofproviding heat into the board 12 or drawing heat out of the board 12.The flexibility to achieve a wide range of temperatures on the board 12,and thus at the electronics device 14, can improve calibration accuracyof the electronic device 14.

In use, the electronics system 10 is brought into contact with portionsof the calibration station 80. When the electronics system 10 and thecalibration station 80 move relatively towards one another, thecalibration computer interface 86 connects to the board interface 16 andcan begin receiving data from the electronics device 14 at the same timethat the thermoelectric device 88 comes into contact with the thermalinterface 52. In the embodiment described, the calibration computerinterface 86 and the board interface 16 are wired interfaces that comeinto contact with one another to create a communication link and arereleasable from one another to break the communication link. Data isreceived through a wired communication between the electronics system 10and the calibration station 80. In another embodiment, the calibrationstation 80 and the board may include wireless interfaces that create awireless link for data transfer and the wireless link sis then broken.

Electric power is provided through the electric power connector 92 tothe calibration computer 84, which powers the calibration computer 84.Electric power is also provided through the electric power connector 92and the transformer 90 to the thermoelectric device 88.

The entire electronics system 10 can begin calibration initially at roomtemperature, e.g. approximately 21° C. The temperature sensor 68 (FIG. 5) provides an output of the temperature to the calibration computer 84.The accelerometer 70 and the gyroscope 72 simultaneously provide outputsto the calibration computer 84 that are associated with the outputtemperature from the temperature sensor 68. Baseline outputs for theaccelerometer and the gyroscope are either known because the device isat rest or are established at a reference temperature, such as at roomtemperature. These baseline outputs are used later in the calibrationprocess to isolate errors in measurements (“offsets”) that areassociated with temperature changes of the sensors.

FIG. 7 illustrates that the calibration computer 84 is connected to thesystem storage 18 and records calibration data 96 in the system storage18 as the calibration offsets are calculated. A first entry in a tableof the calibration data 96 includes the initial temperature (in thisexample, 21° C.), an acceleration offset (calculated by finding thedifference between the acceleration measurement at temperature and theknown acceleration), and an angle offset (calculated by finding thedifference between the gyroscope measurement at temperature and theknown positional information) that are calculated for a giventemperature sensor measurement using inputs from accelerometer 70 andgyroscope 72, respectively.

The thermoelectric device 88 has an upper surface that is at a lowertemperature than room temperature and a lower surface that is at ahigher temperature than room temperature. Heat transfers from the hightemperature, lower surface of the thermoelectric device 88 through theupper surface 54 of the thermal interface 52 into the thermal interface52. The heat transfer is primarily by way of conduction. The heat thenconducts through the third metal layer 38 and first and second sets ofvias 40 and 42 to the first and second metal layers 34 and 36. The heatthen conducts through the first, second and third metal layers 34, 36and 38 from the first region 46 nearest the heat source outward towardthe second region 48. The barriers 62 prevent or at least substantiallyretard transfer of heat from the inner portion 58 to the outer portion60.

Heating of the second region 48 causes its temperature to increase.Conduction of heat through the metal layers 34, 36, 38 and the thermalvias 40, 42 happens rapidly while significantly slower conduction ofheat occurs in the structural material layers 28, 30. Conduction throughtop metal layer 38 evenly distributes heat underneath electronics device14 in the second region 48. The increased temperature of the secondregion 48 causes heat transfer through conduction by connection 74 andthrough passive convection of air surrounding the electronics device 14.This method of heating electronics device 14 closely mimics the fieldconditions that the electronic device 14 will experience. Thetemperature sensor 68 continues to detect the temperature of theelectronics device 14. The calibration computer 84 samples thetemperature of the temperature sensor 68 on a predetermined interval,e.g. every five seconds, or more frequently for improved accuracy. Thecalibration computer 84 also samples outputs from the accelerometer 70and the gyroscope 72 at the same time that the calibration computer 84samples a temperature from the temperature sensor 68. The calibrationcomputer 84 then calculates and stores each temperature and eachacceleration offset and each angle offset with the calibration data 96.As described herein previously, each temperature is associated with anacceleration offset and an angle offset component within the measurementreadings of the accelerometer and gyroscope, respectively. An offsetprofile can be obtained by measuring outputs of each sensor across arange of temperatures, each time subtracting the known value that thesensor should measure from the actual measurement to calculate error.Each temperature thus has a different acceleration offset and angleoffset associated therewith, even though the accelerometer 70 andgyroscope 72 remain stationary from one measurement to the next. In someembodiments, multiple measurements are obtained at each temperature andan average offset is calculated for improved accuracy.

When sufficient data is collected, the calibration station 80 is removedfrom contact with the board 12. The calibration computer interface 86writes the collected calibration data to the system storage 18 anddisconnects from the board interface 16. The thermoelectric device 88disengages from the thermal interface 52. Heat convects and conductsfrom the electronics device 14 until the entire electronics device 14returns to room temperature.

The calibration system and process described above do not requirephysical contact between the calibration station and the electronicsdevice 14 and furthermore do not require forced convection acrosselectronics device 14. Rather, the electronics device 14 is heated byway of conduction through a permanent connection (connectors 74 andmetal lines 76) to the board 12 and by way of passive convection withoutthe need for additional probe contact with or forced air blowing overthe electronics device 14. The electronics device 14 can thus becalibrated against temperature without disturbing the accelerometer 70or the gyroscope 72. This system and process allows for a more accurateoffset calibration while mimicking real field conditions of the sensorson board electronics device 14.

FIG. 8 illustrates the electronics system in conjunction with a fieldcomputer 100, a field computer interface 102 and a controlled system104. The controlled system 104 may be, for example, a virtual reality,augmented reality, or mixed reality device. The field computer 100 isconnected to the field computer interface 102. The controlled system 104is connected to the field computer 100. The field computer 100 may, forexample, be a computer that processes movement data of an augmentedreality viewing system and the controlled system 104 may be a visionprocessing system of the viewing device. The field computer 100 isconnected to the system storage 18 and has access to the calibrationdata 96.

In use, the electronics system 10 is moved, e.g. in linear directions orrotational directions. The accelerometer 70 and the gyroscope 72 detectsuch movement of the electronics system 10. The field computer 100senses signals received from the temperature sensor 68, accelerometer 70and gyroscope 72. The field computer 100 uses the temperature detectedby the temperature sensor 68 to find a corresponding temperature in thecalibration data 96. The calibration data 96 may include the table withdata as hereinbefore described or may include a formula, such as alinear regression, representative of the calibration data. The fieldcomputer 100 retrieves the acceleration offset and the angle offset inthe calibration data 96 corresponding to the temperature measured by thetemperature sensor 68. The field computer 100 then adjusts theacceleration detected by the accelerometer 70 by the acceleration offset(acceleration=measured acceleration−acceleration offset). The fieldcomputer 100 also adjusts an angle measured by the gyroscope 72 by theangle offset corresponding to the temperature (adjusted angle=measuredangle−angle offset). The field computer 100 then provides the adjustedacceleration and the adjusted angle to the controlled system 104. Thecontrolled system 104 utilizes the adjusted acceleration and theadjusted angle in one or more formulas. By way of example, thecontrolled system 104 adjusts placement of a rendered image in anaugmented reality or mixed reality viewing device according to aplacement formula that uses the adjusted acceleration and the adjustedangle received from the field computer 100.

FIG. 9 illustrates an alternate embodiment wherein a thermal conduit isprovided by any known heat spreader that can be built into a chip. Insome embodiments, the heat spreader can be a heat pipe 110. The heatpipe 110 has an evaporator end 112 and a condenser end 114. Theevaporator end 112 is located against or in close proximity to thethermal interface 52 and the condenser end 114 is located in closeproximity to the electronics device 14. In use, the thermal interface 52heats a liquid in the heat pipe 110 and evaporates the liquid. Theresultant vapor flows from the evaporator end 112 to the condenser end114 and condenses. The resulting condensed liquid then flows through awicking system from the condenser end 114 back to the evaporator end112.

FIGS. 1 to 8 illustrate one type of thermal conduit consisting of athermally conductive metal. The design in FIGS. 1 to 8 is relativelyinexpensive to manufacture. FIG. 9 illustrates a different type ofthermal conduit in the form of a heat pipe. A heat pipe may transfermore heat, through flow, than thermally conductive metal but may be moreexpensive to manufacture. The thermal conduit provided by the thermallyconductive metal in FIGS. 1 to 8 and the thermal conduit provided by theheat pipe in FIG. 9 both have a thermal heat transfer capacity that ishigher than a thermal heat transfer capacity of the structural material22 of the board 12 and both form a thermal path between the surface ofthe thermal interface 52 and the electronics device 14.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative and not restrictive of the current invention, andthat this invention is not restricted to the specific constructions andarrangements shown and described since modifications may occur to thoseordinarily skilled in the art.

What is claimed:
 1. An electronics system comprising: a board that includes: a structural material; a thermal conduit on the structural material, the thermal conduit having a thermal conductivity that is higher than a thermal conductivity of the structural material and having a first region, a second region, the first and second regions being horizontally spaced, and a connecting portion connecting the first region to the second region; and a thermal interface on the structural material above the first region of the thermal conduit, the thermal interface having an exposed upper surface and a thermal heat transfer capacity that is higher than the thermal heat transfer capacity of the structural material and being attached to the first region of the thermal conduit; an electronics device mounted to the board above the second region of the thermal conduit, the thermal conduit forming a thermal path between the surface of the thermal interface and the electronics device; and a board interface attached to the board and electrically connected to the electronics device, the board interface being adapted to interchangeably connect to a calibration computer interface of a calibration station having thermoelectric device for releasably contacting the exposed upper surface, and to connect to a field computer interface that is connected to a field computer.
 2. The electronics system of claim 1, wherein the thermal conduit includes a metal conductor.
 3. The electronics system of claim 2, wherein the thermal conduit includes at least two metal layers that are separated by a layer of the structural material.
 4. The electronics system of claim 3, wherein the thermal conduit includes at least one metal via connecting the layers to one another.
 5. The electronics system of claim 4, wherein the thermal conduit includes a plurality of metal vias connecting the layers to one another.
 6. The electronics system of claim 2, wherein the metal conductor is made of a metal that is more thermally conductive than the structural material.
 7. The electronics system of claim 2, wherein the board has at least one metal layer having an inner portion and an outer portion and the structural material forms a barrier between the inner portion and the outer portion, the inner portion forming the thermal conduit, and the thermal interface and the electronics device being located over the inner portion.
 8. The electronics system of claim 7, wherein the metal layer is more electrically conductive than the structural material.
 9. The electronics system of claim 7, wherein the structural material forms a plurality of barriers between the inner portion and the outer portion, wherein the barriers are alternated with portions of the metal layer that connect the inner portion to one another.
 10. The electronics system of claim 1, further comprising: a movement detection device in the electronics device; a system storage; and calibration data on the system storage, the calibration data including a first temperature of the movement detection device; a first output from the movement detection device recorded against the first temperature; and a second temperature of the movement detection device that is different than the first temperature; and a second output from the movement detection device recorded against the second temperature.
 11. The electronics system of claim 10, wherein the movement detection device is an accelerometer.
 12. The electronics system of claim 10, wherein the movement detection device is a gyroscope.
 13. The electronics system of claim 10, further comprising: a temperature detector in the electronics device.
 14. The electronics system of claim 13, further comprising: a field computer; an interface connecting the field computer to the movement detection device and the temperature detector; and a controlled system connected to the field computer.
 15. A method of constructing an electronics system comprising: constructing a board including: forming a thermal conduit on the structural material, the thermal conduit having a thermal heat transfer capacity that is higher than a thermal heat transfer capacity of the structural material and having a first region, a second region, the first and second regions being horizontally spaced, and a connecting portion connecting the first region to the second region; forming a thermal interface on the structural material above the first region of the thermal conduit, the thermal interface having an exposed upper surface and a thermal heat transfer capacity conductivity that is higher than the thermal heat transfer capacity of the structural material and being attached to the first region of the thermal conduit; mounting an electronics device to the board above the second region of the thermal conduit, the thermal conduit forming a thermal path between the surface of the thermal interface and the electronics device; and attaching a board interface to the board and electrically connected to the electronics device, the board interface being adapted to interchangeably connect to a calibration computer interface of a calibration station having thermoelectric device for releasably contacting the exposed upper surface, and to connect to a field computer interface that is connected to a field computer. 